K. I. Pashkevich

2,4-Bridged 1,5-bis(fluoroalkyl)-1,3,5-triketones: synthesis and properties

Abstract Symmetrical and unsymmetrical bis-fluoroacylcyclopentanones and cyclohexanones were synthesized. NMR data reveal that the keto–enol tautomeric equilibrium is changed markedly by the presence of a trimethylene bridge compared to an ethylene moiety. A considerable influence of the fluoroalkyl chain length was found for 2,6-(bisfluoroacyl)cyclohexanones.

Fluoroalkyl-containing lithium β-diketonates in the synthesis of 1,2,4-triazolo[1,5-a]pyrimidines

Cyclocondensation of fluorine-containing lithium β-diketonates with 3-amino-1,2,4-triazoles afforded 7-fluoromethyl-1,2,4-triazolo[1,5-a]pyrimidines.

Synthesis of fluorine-containing functionalized isoxazolines

The reaction of regioisomeric fluoroalkyl-containing (3-aminovinylketones with hydroxylamine generatedin situ from hydroxylamine sulfate, afforded 5-hydroxy- or 5-amino-5fluoroalkyl-Δ2-isoxazolines.

Synthesis of (7-polyfluoroalkyl)pyrazolo[1,5-a]pyrimidines based on lithium fluorine-containing β-diketonates

The reactions of Li enolates of fluorine-containing β-diketones with 3-aminopyrazoles afforded (7-polyfluoroalkyl)pyrazolo[1,5-a]pyrimidines. The structure of 3-bromo-2-methyl-5-phenyl-7-trifluoromethylpyrazolo[1,5-a]pyrimidine was established by X-ray diffraction analysis.

Determination of Chloroacetic Acids in Drinking Water by Reaction Gas Chromatography

A procedure was developed for determining chloroacetic acids in drinking water. The procedure is based on solid-phase extraction followed by the conversion of chloroacetic acids to trifluoroacetic esters and their separation and determination by gas–liquid chromatography with an electron capture detector. Esterification conditions were optimized. The procedure was used for analyzing samples of drinking water.

Synthesis of bis(polyfluoroalkyl)-1,3,5-triketones

A preparative procedure was developed for the synthesis of polyfluoroalkyl-1,3,5-triketones by condensation of acetone or fluorinated methyl β-diketones with methyl perfluorocarboxylates in the presence of LiH. In the case of CF3 substituents, the formation of triketone was accompanied by the formation of its cyclic hydrate, viz., of dihydroxytetrahydropyranone.

Synthesis of 3-fluoroalkyl-2-aziridinyl ketones

Simple and efficient methods for the synthesis oftrans-3-fluoroalkyl-2-aziridinyl ketones from polyfluorinated α,β-enones have been developed.

Synthesis of polyfluoroalkyl-containing 1,3,5-triketones

Abstract Synthesis of polyfluoro 1,3,5-triketones by modification of Claisen condensation is described.

Interaction of fluoroalkyl-containing β-diketones with amines

The composition of products of the interaction of asymmetric fluoroalkyl-containing β-diketones with amines was studied. Mixtures of regioisomeric β-aminovinylketones and products of cleavage and secondary condensation are formed, depending on the temperature, the solvent, the nature of the fluorinated and nonfluorinated substituents in the β-diketone, and the basicity of the amine. The major product is a β-aminovinylketone in which the NH2 group is removed from the fluoroalkyl substituent. No β-aminovinylimines, products of condensation involving two electrophilic centers, were observed.

Polyfluorinated ?,?-unsaturated ketones

Conclusions1.β-Hydroxyketones and α,β-unsaturated ketones with β-fluoroalkyl substituents have been prepared. It has been shown that the latter exist predominantly in the trans-s-cis form irrespective of the length of the fluoroalkyl substituent.2.As with the hydrocarbon analogs and the isomeric polyfluorinated β-aminovinylketones, polyfluorinated α,β-unsaturated ketones react with nucleophilic reagents to form β-substituted ketones.